First of all, thank you for your time; i will give a little background:

My father, who is a retired old man a bit old fashioned but he is always trying to adapt to the new era (smart phones, computers...) has a lot of home videos like family dinners, weddings, parties... that kind of stuff recorded on super 8, he is now turning all the analogic films into a digital ones and editing them just to get all his personal videos shorted and easily indexed. The point is that he is the typical person who wants to do the things properly done, that means he add captions (subtitles) on videos, and here is when the problem starts:

Instead of using captions/subtitle option, he thought he could do the work with the legacy titles option (File --> New --> Legacy title) so he can "easily" make them and positioning and syncing the subtitle in any part of the video... Yes, that means a lot of time consuming (we are talking about 4+ hours per event or something like that...), i tried to warned him about this situation but he is sttuborn as an ox and when he noticed he couldn't export only the subtitle (*.srt or similar), he called me and beg to me to help him to solve his problem (because the only option to show the subtitle in the final video it's to hardsub them i think). At the moment he has like 8 proyects with legacy titles "embedded" (around 2000 lines per proyect........... probably more). I tried without success export only the titles. I need some help with this, maybe there is a 3rd party tool than can make something with this, or maybe Premiere Pro has an answer itself.

One of the options i handle if it won't be another solution (please, i need one) it's to export the entire video without the video itself and only the lecagy titles in a black background and then using an OCR to get and *.srt file, so the *.srt it's synchronized and it won't be necessary to resync again the subtitles if it would be necessary to rewrite the subtitles in a proper way... But im not sure if this is a good idea.

Rewriting the subtitles in a proper way is not an option, not yet, he is retired, but he hates wasting time (ironic )

that means he add captions (subtitles) on videos, and here is when the problem starts:

Instead of using captions/subtitle option, he thought he could do the work with the legacy titles

he couldn't export only the subtitle (*.srt or similar), he called me and beg to me to help him to solve his problem

I tried without success export only the titles.

Sorry. Your dad should have started by using the open captions function if the end goal was to export the subtitles.

maybe there is a 3rd party tool than can make something with this, or maybe Premiere Pro has an answer itself.

There isn't one I am aware of. You might try uploading the videos to YouTube where automatic open captioning takes place. You can then adjust these captions in the YouTube UI. Does that help?

it's to export the entire video without the video itself and only the lecagy titles in a black background and then using an OCR to get and *.srt file, so the *.srt it's synchronized and it won't be necessary to resync again the subtitles

Bottom line: As Kevin says, YouTube auto-captioning would help your father a lot. This uses voice recognition to create the captions. It won't work for regular "titles" he is adding to describe action, add a date, etc. The YouTube captions can be edited and exported. I had not played with this, and it is very nice. On my sample, they are 2 lines per caption. You could also use a (free) captioning app like Subtitle Edit to edit these.

As Kevin quoted, you describe:

that means he add captions (subtitles) on videos, and here is when the problem starts:

Instead of using captions/subtitle option, he thought he could do the work with the legacy titles

But if he created legacy titles, these are not subtitles or captions at all, but "titles," correct? I don't know that it matters; I don't know of any way to pull just his text out.

Well, thanks for your time. I was aware about youtube captioning, but... just think they come from a super 8 movie, just imagine audio quality (poor microphone), in addition, many conversations are like whispers, not whispers, but you know, they are home videos, the voices are not pointing to the microphone, and this implies wrong youtube captioning (i had tried before in various context).

What he did it was like making a clear/transparent "subtitleLine1.psd" with text "Oh hello dear, ¿are you drunk?" on photoshop, then, import to premiere pro and syncing in the exact moment and positioning in any part of the video (for each line...) but with the legacy titles tools that provides Premiere Pro, (it's not necesary to use Photoshop, just saying this to clarify what i think it's happening, in other words, a similar concept about subtitles tracks on DVD (idx/sub)).

Yes juanmario, that was the thing i did.

Any ideas will be appreciated, in the meantime i will dust off my old god subtitles tools a.k.a SubRip

Well you will think i'm not a humble person, but guys, "One of the options i handle if it won't be another solution (please, i need one) it's to export the entire video without the video itself and only the lecagy titles in a black background and then using an OCR to get and *.srt file, so the *.srt it's synchronized and it won't be necessary to resync again the subtitles if it would be necessary to rewrite the subtitles in a proper way... But im not sure if this is a good idea." THIS HAS BEEN DEFINITELY A BRILLANT AND PERFECT IDEA, WORKED LIKE A CHARM AND IT ONLY REQUIRED TO ME LIKE 4 HOURS OF HARD WORK TO FILL THE MATRIX REQUIRED TO DO THE OCR WORK FOR ALL VIDEOS. AGAIN, SUBRIP SAVE THE DAY.

So if anyone (i doubt it, but you can ask me) has to deal with a similar problem, i will suggest my own thoughts: try to get the titles in a black background with the purpose of easing OCR when you try to pull the text out. I had to turn the black video with titles into something that Subrip could easily understand and handle: don't try to import something bigger than 4GB, or with a big resolution (1980x1080 it's too big); use an .avi container with it's own Divx codecs...(don't use MKV or similar) if you don't want to deal with AviSynth (headache). So i will mark this answer as Correct answer.